March 21 (Reuters) - Wall Street was on track for a lower opening on Wednesday as traders moved cautiously ahead of an expected Federal Reserve interest rate hike and continuing fallout from Facebook Inc's data privacy breach.

Concerns about the impact of U.S. tariffs on global trade also made investors uneasy. Equity futures took a dip after the Wall Street Journal that China was planning countermeasures to the Trump administration's threatened import duties, including levies on U.S. agricultural exports from farm belt states.

President Donald Trump is expected to unveil up to $60 billion in new tariffs on Chinese imports by Friday, sources had told Reuters.

Fears over a trade war also come as markets are anxious for clarity about what kind of monetary policy regime will be pursued by new Fed chair Jerome Powell.

"There has been some worry off-and-on for sometime now. Fear of a trade war versus maybe some hope that it's not going to be so bad or it's going to be more limited," said Scott Brown, chief economist at Raymond James in St. Petersburg, Florida.

"There is going to be a little bit more fear this morning, especially heading into the Fed meeting. He's (Powell) is going get asked about tariffs, its implications for the economy and for the Fed policy."

The Fed is widely seen raising its benchmark interest rate by 25 basis points when it concludes the first meeting of the Jerome Powell era at 2:00 p.m. ET.

An increase would mark its sixth hike since late 2015 when the U.S. central bank started gradually tightening monetary policy following a period of near-zero interest rates in the aftermath of financial crisis in 2008. It would be the first since Powell succeeded Janet Yellen as Fed chair in February.

While markets are sure about the quarter-point hike, they are less confident of what the Fed signals next: three hikes this year as previously forecast by policy makers or four. Some investors believe that corporate tax cuts and recent hints of inflation pressures will push policymakers to add an additional increase beyond the expected three.

One worry among equity investors is faster rate hikes could dent the appeal of stocks relative to bonds as fixed income securities become less pricey than they've been in the low-rate era. Stocks, meanwhile, remain relatively expensive despite recent pull backs.

Ahead of the Fed announcement, 2-year Treasury note yields , which are highly sensitive to Fed policy expectations, hit their highest in more than nine years on Wednesday morning at 2.35 percent.

Aside from the Fed, tech shares looked under pressure again as Facebook's data privacy travails persisted. Its shares were down 0.8 percent in premarket trading, on track for its third day of losses amid uproar over the alleged misuse of users' data.

Facebook shares have lost about 9 percent in just two days, and hurt shares of other social media companies such as Twitter and Snap Inc as the issue raised broader questions about consumer privacy and whether tougher regulation is on the horizon.

By 8:50 a.m. ET, Nasdaq 100 e-minis were down 26 points. Dow e-minis were off by 35 points, and S&P 500 e-minis were 4 points lower.

General Mills slid more than 8 percent after the Cheerios cereal maker cut its yearly earnings forecast, citing a sharp increase in freight and commodity costs. (Reporting by Sruthi Shankar in Bengaluru Editing by Dan Burns)